2021/10/18 by Victor Funk, Funk, Victor, Koloman Wagner +20 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Chalcogenide Semiconductor Thin Films #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Perovskite Materials and Applications #Semiconductor Quantum Structures and Devices
paper · pdf · doi:10.48550/arxiv.2110.09583
openalex publication_date 2021/10/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report an experimental study of temperature-dependent spectral lineshapes\nof phonon side-band emission stemming from dark excitons in monolayer and\nbilayer WSe2. Using photoluminescence spectroscopy in the range from 4 to\n100K, we observe a pronounced asymmetry in the phonon-assisted luminescence\nfrom momentum-indirect exciton reservoirs. We demonstrate that the\ncorresponding spectral profiles are distinct from those of bright excitons with\ndirect radiative decay pathways. The lineshape asymmetry reflects thermal\ndistribution of exciton states with finite center-of-mass momenta,\ncharacteristic for phonon sideband emission. The extracted temperature of the\nexciton reservoirs is found to generally follow that of the crystal lattice,\nwith deviations reflecting overheated populations. The latter are most\npronounced in the bilayer case and at lowest temperatures. Our results add to\nthe understanding of phonon-assisted recombination of momentum-dark excitons\nand, more generally, establish means to access the thermal distribution of\nfinite-momentum excitons in atomically thin semiconductors with indirect\nbandgaps.\n